A 42-year-old was left for dead in the street after he was attacked by a jealous boyfriend, a court heard.
Richard Reynolds lost his life 12 days after the violent assault by powerfully built Daniel Duckworth, a jury was told.
Richard, a tree surgeon, was set upon after he light-heartedly flirted with Duckworth’s girlfriend, Michelle Burrell.
Prosecutor Stephen Wood told Bradford Crown Court Duckworth, 36, was “consumed with jealousy” when he saw them in Wharf Street, Sowerby Bridge, in May.
He marched over to the group, which also included a colleague of Mr Reynolds. Mr Wood said without any warning Duckworth punched Mr Reynolds twice in the head, kicked at him while he was on the ground and aimed a punch at his friend, Martin Potts.
The court heard Mr Reynolds struck the back of his head on the ground as he fell. He died in hospital 12 days later.
Mr Wood said the prosecution did not suggest Duckworth intended to kill Mr Reynolds or cause serious injury.
But he said the blow that knocked him to the ground was an unlawful act of violence without any justification and it caused his death.
Duckworth, of West Street, Sowerby Bridge, has denied a charge of manslaughter and has also pleaded not guilty to assaulting Mr Potts.
Mr Wood said Mr Reynolds had engaged Duckworth’s girlfriend Michelle Burrell in conversation and “light-hearted flirtation” when he and his friend saw her alone leaning on a wall.
Duckworth, who had earlier been with Miss Burrell in the nearby Roxy’s nightclub, came over and punched Mr Reynolds in the face possibly catching him off-guard.
Mr Wood said Miss Burrell shouted at Duckworth: “Don’t do it again, leave him alone.”
“But the defendant didn’t stop,” said Mr Wood. “He was, the prosecution submit, by this time consumed by a rage borne out of an all-consuming jealousy.”
Mr Reynolds was subjected to another powerful punch which caused him to fall heavily to the ground.
Mr Potts described the impact of Mr Reynolds’ head as making a “hollow” sound saying it was shocking and made him cringe.
Fearing for his safety after Duckworth threw a punch at him Mr Potts ran off, but when he returned he found members of the public assisting his friend.
“Ladies and gentlemen Mr Reynolds, on the floor being tended to in the way described, the prosecution submit his plight would have been obvious to anyone; unconscious and bleeding,” said Mr Wood.
“But the defendant quite literally left him for dead and walked off back to Roxy’s Bar. He did not give Mr Reynolds a second thought.’’
Duckworth later claimed during police interviews that he had only intervened to protect his girlfriend because the two men were being sexually crude and abusive to her.
He denied punching Mr Reynolds at all and suggested that he fallen over because he was so drunk
But Mr Wood referred to one witness who claimed to have seen Duckworth “side-swipe” his girlfriend as they argued on their way back to the club.
The defendant was initially questioned over the incident while Mr Reynolds was still being treated in hospital, but after he was told about his subsequent death Duckworth said: “I feel down, but I ain’t gonna do owt stupid. I could apologise to his family but I wouldn’t really mean it. If someone was messing with your girlfriend what would you do? All I did was push him.”
The trial is expected to last about two weeks.